Entertainment

Loan repaid, with interest

There are bona fide stars in the re vival of Ken Ludwig’s “Lend Me a Tenor,” which opened last night: Tony Shalhoub from “Monk” and Anthony LaPaglia, a Tony winner for “A View From the Bridge” in 1998.

But it’s Justin Bartha — the missing groom from the hit movie “The Hangover” — who takes the final bow.

And Bartha deserves it: He’s the engine that powers this show. He doesn’t just make his Broadway debut, he dynamites the doors open.

Happily, the rest of the cast rises to the challenge, and “Lend Me a Tenor” is exactly what it needs to be: hilarious.

It’s often said that a good comedy must be like a well-oiled machine. Actor-turned-director Stanley Tucci must have had a can of WD-40 handy. Doors get slammed a lot in this show, but there aren’t many creaky hinges.

Admittedly, the plot is ludicrous — but then so was the one in the stewardess farce “Boeing-Boeing,” the closest equivalent to this “Tenor” in recent Broadway memory. You don’t sign up for plausibility.

It’s 1934, and a famous Italian tenor, Tito Merelli (LaPaglia), is about to sing “Othello” at the Cleveland Grand Opera’s gala — but he’s passed out and can’t be revived. The opera’s desperate manager, Saunders (Shalhoub), goads his meek, singer-wannabe assistant, Max (Bartha), into stepping in as Tito, in full Moor makeup.

Of course, the mix wouldn’t be complete without some volatile women: Max’s girlfriend, Maggie (Mary Catherine Garrison), crushed out on Tito; the star’s hot-tempered wife, Maria (the scene-stealing Jan Maxwell); and ambitious soprano Diana (Jennifer Laura Thompson).

Identities are mistaken, characters run in and out of rooms (and closets), and people often converse about completely different topics without realizing it.

The last is as far as Ludwig’s wit goes — his lines usually aren’t funny in and of themselves — so it’s not surprising that the nonverbal shenanigans score the biggest laughs. There’s memorable hissing from Maxwell, squealing from LaPaglia and screeching from Bartha, while Shalhoub delivers pregnant pauses big enough for octuplets.

And of course the slapstick is virtually nonstop, with people tumbling, pratfalling, throwing themselves onto beds and couches, and spitting various items into the audience.

Cheap stuff? Yes, and it’s wonderful.

True, the intensity occasionally dips in the second act. But every time Bartha is onstage, looking like Sammy Davis Jr. in a Renaissance Faire getup, he brings down the house. The actor’s command of the mechanics of comedy is a joy to behold.

Lend a tenor? We just bought one lock, stock and barrel.

elisabeth.vincentelli@nypost.com